1. Field of the Invention
This invention relates generally to a paper sheet stripper device to be used in a paper sheet dispenser, and particularly to an improvement in a suction head assembly for sucking paper sheets one by one and for passing the same to a paper sheet take-up assembly located on the way to a passage through which paper sheets are conveyed.
2. Prior Art
A typical suction head assembly of the prior art used in a bank note dispenser is shown in FIGS. 1(a) and 1(b). Firstly referring to FIG. 1(a), the known suction head assembly comprises a reciprocating vacuum pump 1 and a suction head 2. The suction head 2 is pneumatically connected to the vacuum pump 1 and swingable between the position shown by the solid line and the position shown by the dot-and-dash line. The suction pressure generated in the pump 1 varies periodically as represented by the sinuous curve shown in FIG. 1(b). The suction head 2 is swung from the position shown by the solid line to the position shown by the dot-and-dash line, as shown in FIG. 1(a) when the pressure applied thereon assumes a value within the range shown by l in FIG. 1(b), whereby a lower portion of a bank note is sucked by the suction head 2 and stripped from a bundle 3 of bank notes to be allowed to engage with a take-up roller assembly 4. When the pressure applied to the suction head 2 is changed to atmospheric pressure, the sucked bank note is passed to the take-up roller assembly 4 to be conveyed by a conveyer assembly 5.
However, by the use of the known combination of suction head and pump described above, a malfunction in sucking operation frequently occurs due to fluctuation in suction pressure. Moreover, the negative suction pressure applied on the suction head 2 assumes a high enough value for sucking the bank note only during the time denoted by l in FIG. 1(b). This necessitates the suction head 2 to be swung at a precise timing. As a result, the mechanism for swinging the suction head 2 is inevitably complicated. A further disadvantage of the known suction head is that the bank note sucked thereby and moved to the take-up position facing the rollers of the take-up roller assembly 4 tends to be swept off by the air blown from the port of the suction head 2 when the pressure applied on the head 2 is increased from the minimum value. Under the disadvantageous influence of the air flow caused by the pressure change in the vicinity of the port of the suction head 2, the bank note passed to the take-up roller assembly 4 and moving to the conveyer assembly 5 is not steadily moved along the predetermined passage but often gets jammed or broken.